Control system for apparatus



June 12,' 1934. J NGEDYK 1,962,742

CONTROL SYSTEM FOR APPARATUS Filed Oct. 8. 1936 lm/enfor" Hal 1h Jo yeqd Patented June 12, 1934 CONTROL SYSTEM FOR. APPARATUS Ralph Jongedyk, Hinsdale, 111., assignor to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application October 8, 1930, Serial No. 487,268

11 Claims. (Cl. 192-429) This invention relates to a control system for apparatus, and more particularly to a safety device for use with machinery having moving parts.

An object of this invention is to provide a 5 sensitive and efficient control system for guarding a machine operator against an injury that might be caused'by a moving part of the machine. In accordance with this object one embodiment of the invention comprises means for projecting and reflecting a beam of light a number of times in a plane located adjacent to the path of a moving part of a machine, and a light sensitive means responsive to the projected beam. The light sensitive means is connected to a vacuum tube rectifying and amplifying circuit which includes a controlling relay which operates upon interruption of the beam, as by movement of the operator's hand through the beam, to stop the machine. A timing cam actuated by the machine and electrically connected to the controlling relay-renders the latter effective only during that stage of machine operation wherein an injury to the operator would be likely to occur.

A clear understanding of the invention will be had from the following description of one specific embodiment thereof as illustrated in the accompanying drawing, wherein the single figure illustrates diagrammatically an apparatus embodying the invention.

The single figure of the drawing is a fragmentary view of a punch press and motor showing the control system diagrammatically.

Referring now to the drawing, the reference numeral 5 indicates a punch press having a reciprocating ram 6 or other moving part from which it is intended to protect the operator against a possible injury by means of the safety device. A source of light 7 which consists of an incandescent electric lamp connected to a pair of terminals 8 extending from a source of alternating current (not shown) furnishes light for a'pair of collimating lenses 9 which project a beam of the light 10 across the space adjacent and in front of a ram 6 of the punch press. Right triangular prisms 13-13 are arranged on forms of radiant energy may of course be substituted for the beam 10.

In order to supply the photo-electric cell '14 with electrical current at the proper voltage, a

winding connected to the terminals 8, and one of its secondary windings is connected by a pair of conductors 16 to the filament of a vacuum tube 1'7, a variable tap 18 being connected to this secondary winding and adjustably engaging a potentiometer 19 which is connected in parallel with the other secondary winding of the transformer. A conductor 20 connects one terminal of this latter secondary winding to a variable condenser 23 and' a conductor 24 extends therefrom and connects with the grid electrode of the vacuum tube 17 and to the metal or potassium coating connecting electrode 25 of the photoelectric cell 14. A second conductor 26 connects the other terminal of this secondary winding to a controlling relay 27, across the terminals of which is connected a condenser 28, and aconductor 29 extends from this relay to the plate electrode of the vacuum tube 1'7 and thence to the central electrode ,30 of the photo-electric so cell 14.

The controlling relay 27 has a stationary contact member 33 which is connected by a conductor 34 with one of the terminals 8, and the armature 35 of this relay is connected by a conducs5 tor 36 to one terminal of a relay 37, the other terminal of which is connected to -a conductor 38 which extends to the other terminal 8, sothat the armature 35 controls the energization of the relay 37 through the current supplied from the terminals}! when the armature 35 is attracted into engagement with the stationary member 33 by the coil 27. A movable contact member 39 connected to the conductor 36 and a stationary contact member 40 connected to the conductor 34 are designed to short circuit the armature 35 and stationary contact member 33 when a cam 43, rotated in timed relation by the machine 5, forces the movable contact member 39 into engagement with the stationary contact transformer 15 is provided, having its primary 60 both sides of the machine 5 to receive and refleet the beam 10 in adjacent paths which provide a screen or plane of light substantially cov- 50 ering the area in front of the machine 5 and 55 ported for finally receiving the beam 10. Other member 40. The relay 37 has its stationary contact member 44 connected by a conductor 46 to one terminal of the motor 47- driving the punch press 5 and the armature 45 of this relay has a conductor 48 leading therefrom to one of a pair of terminals 49 for supplying current to the motor 47, the other terminal 49 being connected directly to the motor.

In the operation of the above described protecting device alternating current will be supto flow through the cell while the beam is striking the cell, as is well understood in the photoelectric cell art. The adjustable tap 18 is so positioned relative to the potentiometer 19 as to provide the proper amount of current in the filament of the tube 17, and the variable condenser 23 is so adjusted as to properly negatively bias the metal or potassium coating connecting electrode 25 of the photo-electric cell 14 and the grid electrode'of-the vacuum tube 17 to effect the proper operation of these parts, as is well understood'in the vacuum tube and photoeelectric cell art.

Assuming now that the ram 6.is being moved downwardly by the motor 47 and that the operators hand has inadvertently been projectedthrough the plane .or screen of light formed by the beam' 10 into a position to be injured by the ram 6, it will be noted that the beam will thereby be interrupted causing an interruption in the current flowing through the photo-electric cell 14, and the vacuum tube 17 will amplify this condition and cause deenergization of the relay 27 which is supplied with current through the tube 17, and the relay 27 being deenergized, the

armature 35 thereof will then move out of contact with the stationary contact member 33 and break the circuit through the relay 37 supplied from theterminals 8, thereby deenergizing the relay.37 and causing the armature thereof -to move out of contact with the stationary contact member 44. This latter disengagement of the armature 45 with the member 44,breaks-the supply circuit to the motor 47 from the supply terminals 49 and causes the machine 5 to stop.

,In addition to cutting ofi the supply of energy to the motor, the relay 27 may be arranged to control brake and clutch operating solenoids (not shown) to arrest the downward movement oi: the ram 6 more quickly. It is therefore apparent that this protective device efficiently prevents the operator from injury by the ram 6. When the ram is on the upward movement and the operator is removing and placing material thereunder from the downward working stroke, the cam 43, which is rotated by the crank shaft of the machine 5, forces the contact member 39 into engagement with .the member 40 to short circuit the armature 33 and stationary contact member 35 so that theinterruption in the beam 10 due to the operator's hand moving therethrough and causing the armature 35 to break engage- -ment with the member 33 at this time will have of a beam of said screen for 1,962,742 plied the incandescent lamp 7 from the supply only by the scope of the appended claims.

What is claimed is:

1. In a safety device for a machine having a moving part, means for projecting a beam of radiant energy adjacent the path of the moving part, a plurality of reflectors for producing alight screen, and means responsive to an interception arresting the movement of the moving part. 1

2, In a safety device for a machine having a continuously moving part, means for projecting a beam of radiant energy adjacent the path of the moving part, means responsive to an interruption of the beam for arresting the movement of the moving part and causing the part to continue its movement when the interruption ceases, and means rendering said responsive means inoperative during a predetermined portion of the working cycle of the machine.

3. In a device for guarding a moving part 01' a machine, means for projecting a beam of light adjacent the path of the moving part, means for producing a plurality of beams to form alight screen a light sensitive means for receiving one beam of the screen, and means controlled by the light sensitive means and responding to an interception in a beam for arresting the movement of the moving part.

4. In a device for guarding a moving part of a machine, means for projecting a beam of light adjacent 1 the path of the moving part, a. light sensitive meansifor receiving the beam, a vacuum controlled by the vacuum tube for arresting the movement of the moving part upon said decrease in current.

5. In a device for guarding a moving part of a machine, means for projecting a beam of light adjacent the path of the moving part, a reflector for producing a light screen, a light sensitive means for receiving the beam. .means controlled by the light sensitive means to stop the machine upon interruption of the light beam, and means for rendering the last means effective only during a predetermined movement of the moving part.

6. In a device for guarding a moving part-of a machine means for projecting a beam of light several times across an area adjacent the path of the moving part to form a light screen, a vacuum tube circuit affected by interruptions in the beam, and a pair of relays controlled by the vacuum tube circuit for stopping the machine upon interruption of the beam.

7. In a device for guarding a moving part of I a machine, means including an amplifying circuit a machine, means for projecting a beam of iight in adjacent alternate paths adjacent the moving part, a photo-electric cell for receiving the beam and detecting interruptions therein, a vacuum tube circuit for supplying the cell with rectified current. a pair of relays actuated by the vacuum tube circuit for controlling the machine, and a timing cam rotated by the machine for rendering the relays effective at predetermined intervals.

9. In a safety device for a machine having a moving part, a light source, means for reflecting the light from said source back and forth in substantially parallel paths to form alight screen, a light sensitive device in the path of said refiected light, and means responsive to the interception of a light beam in said screen for stopping the machine.

10. In a safety device for a machine having a moving part, means for projecting a beam of light adjacent the path of the moving part, a light sensitive device, a motor for driving said machine, means associated with said light sensitive device for arresting the movement of said motor upon the interception of said light beam, and means actuated by the motor for rendering said arresting means ineifective during predetermined intervals.

11. In a safety device for a machine having a moving part, a motor for driving said machine, including a motorcircuit, a control relay in said circuit, a relay circuit, a pair of parallel relays in said relay circuit, one of said parallel relays being actuated at predetermined intervals by said motor, a light sensitive device for actuating the other of said parallel relays, and a source of light effective upon interception of a beam of light therefrom for causing said light sensitive device to actuate the parallel relay associated therewith.

RALPH JONGEDYK. 

